Method of machining a friction roller

ABSTRACT

A friction roller and a method for producing a friction roller suitable for driving a spinning or twisting tube at high rotational speeds, the roller having tube-engaging driving surfaces formed of a wear-resistant resilient synthetic resin (such as polyurethane), the method comprising finishing the driving surfaces of the roller by machining them while the roller is being rotated at the maximum expected driving speed, which may be of the order of 30,000 to 40,000 r.p.m.

United States Patent Gassner [54] METHOD OF MACHINING A FRICTION ROLLER [72] Inventor:

[73] Assignee:

Hans Gassner, Schweinfurt, Germany Kugelfischer Georg Schafer & Co., Schweinfurt, Germany [22] Filed: Jan. 5, 1970 [21] Appl.No.: 685

[30] Foreign Application Priority Data Jan. 4, 1969 Germany ..P 19 00 402.5

[52] US. Cl. ..82/1 C, 51/289 R, 29/110 1 [58] Field of Search ..82/l C,DlG. 8;5l/289R [56] References Cited UNITED STATES PATENTS 1,920,209 8/1933 Norton ..82/1 C X 1 July 4, 1972 998,734 7/1911 Alexanderson ..82/1 C X FOREIGN PATENTS OR APPLICATIONS 616,204 1/1949 Great Britain ..82/1 C Primary Examiner-Francis S. Husar Attorney-Stevens, Davis, Miller & Mosher [5 7] ABSTRACT A friction roller and a method for producing a friction roller suitable for driving a spinning or twisting tube at high rotational speeds, the roller having tube-engaging driving surfaces formed of a wear-resistant resilient synthetic resin (such as polyurethane), the method comprising finishing the driving surfaces of the roller by machining them while the roller is being rotated at the maximum expected driving speed, which may be of the order of 30,000 to 40,000 rpm.

3 Claims, 5 Drawing Figures PATENTEDJUU4 Ian 3.673.897

SHEET 10F 2 5 FIG. 1

FIG. 2

INVENTOR HANS GASSN ER ATTORNEYS PKTENT'EBJULM I972 sum ear FIG.5

ATTORNEYS METHOD OF MACHINING A FRICTION ROLLER This invention relates to improvements in friction rollers for driving high-speed spinning or twisting tubes. More particularly, this invention relates to friction rollers which have driving surfaces for engagement with the tube and which are formed of a wear-resistant resilient synthetic resin.

Such friction rollers are already known, and they have been used satisfactorily for driving Spinning or twisting tubes at speeds of up to about 300,000 r.p.m. However, with higher rotational speeds, especially speeds up to at least 600,000 r.p.m., it has been found that the tube runs irregularly and vibrates which results in variations in its rotational speed which depart from that speed which is required.

Investigations have shown that when such friction rollers are used at these higher rotational speeds, the driving surfaces made of wear-resistant resilient synthetic resin deform or deflect so that the configuration of the driving surfaces is noncylindrical. Although the driving surfaces of these rollers may be machined to give an extremely fine and accurate surface finish, it has not heretofore been possible to overcome the above-mentioned problem.

Consequently, the use of friction rollers having driving surfaces of a wear-resistant resilient synthetic resin, especially those made of polyurethane, cannot be contemplated for such relatively high rotational speeds.

An object of the present invention is to provide a method for producing a friction roller of the kind previously referred to, but having a special finishing step for the driving surfaces in order to overcome the aforementioned problems.

A further object of the invention is to provide a particular form of friction roller having driving surfaces which are of a configuration suitable for driving a spinning or twisting tube, such as a false twist tube, at extremely high rotational speeds.

Accordingly, the present invention provides a novel method for producing a friction roller suitable for driving a spinning or twisting tube at very high rotational speeds, the roller having driving surfaces forengagement with the tube which are formed of a weanresistant resilient synthetic resin, the method comprising finishing the driving surfaces of the roller by machining them while the roller is rotated at the maximum expected driving speed.

Furthermore, the present invention also provides a novel friction roller suitable for driving a spinning or twisting tube at high rotational speeds and comprising a body having driving surfaces formed of a wearresistant resilient synthetic resin, the driving surfaces having a configuration such that when the roller is rotated at the desired very high driving speeds the driving surfaces are cylindrical, but when the roller is stationary the driving surfaces are non-cylindrical.

By way of example, the present invention will now be described with reference to a preferred embodiment depicted in the accompanying drawing wherein:

FIG. 1 is a plan view of a friction roller mounted on a driving spindle;

FIG. 2 is an end view of the friction roller depicted in FIG.

FIG. 3 is an end view of a roller produced in the conventional manner, and of conventional form. The solid line depicts the configuration of the driving surfaces when the roller is rotated at extra high speeds of revolution, and the dashed line depicts the configuration of the periphery when the roller is at rest;

FIG. 4 is an end view similar to FIG. 3 of a roller made and having a configuration in accordance with the present invention. In this instance, the dashed line depicts the configuration of the periphery of the roller at extra high speeds of revolution, and the solid line depicts the configuration of the periphery when the roller is at rest; and

FIG. 5 is a schematic view of a possible machining operation on the roller while it is being rotated.

Referring to FIG. 1 of the accompanying drawing, a spindle 1 is mounted for rotation in a housing 3 containing roller bearings. A friction roller body is mounted on one end 5 of the spindle 1 by press fitting. The friction roller body 7 includes axially spaced apart flanges which provide driving surfaces 9, 1 1.

The body 7 is made of a wear-resistant resilient synthetic resin, and preferably polyurethane. The body 7 is machined to the required configuration when it is mounted on the spindle 1. This is necessary because of the high degree of accuracy required for the driving surfaces 9, ll of the body 7 necessary for driving high-speed spinning or twisting tubes such as, e.g., false twist tubes.

Hitherto, this machining has been carried out while rotating the roller body at the normal relatively low speeds which are conventionally used for turning or grinding processes. These normal rotational speeds are substantially lower than the actual running speeds of the friction roller while driving the spinning or twisting tube with which it is in engagement.

With particular reference to FIG. 3, a friction roller prepared and machined in this conventional manner will have a truly cylindrical surface 9 when the fiiction roller is at rest. However, when the friction roller is rotated at the operating speed of 30,000 to 40,000 r.p.m., as is necessary for driving the spinning or twisting tube at the desired speeds of up to 600,000 r.p.m., the driving surface does not retain its exact geometrical cylindrical shape because of the deformation or deflection of the wear-resistant resilient synthetic resin. The configuration of the driving surfaces at such high rotational speeds of the friction roller is indicated by the line 13. It is believed that this deformation or deflection of the driving surface is a consequence of the unavoidable inhomogenity of the synthetic resin.

It will be appreciated that the configuration of the periphery 13 is unsuitable for driving spinning or twisting tubes at extra high speeds because of the vibrations which would be set up in the twisting tube when driven by such an irregular configuration.

With reference to FIG. 4, the driving surface 15 has an exact geometrical cylindrical configuration at the operating speed of 30,000 to 40,000 r.p.m., and the configuration of the driving surface 17 when at rest is of non-cylindrical configuration. The peripheral configuration of the driving surface when at rest is of smaller diameter than when the roller is rotated at such very high rotational speeds.

The configuration of the driving surface depicted in FIG. 4 is obtained by subjecting the friction roller to a finishing machining operation in which a diamond tool or the like machines the driving surface while it is rotating at the maximum running speed to be expected, for example at the 30,000 to 40,000 r.p.m. aforementioned. It will be appreciated that when the friction roller is rotated at such very high speeds while being machined, any non-uniform raised portions of the driving surfaces which only become apparent at such very high speeds will be removed and the roller is thus machined in the rotating stressed condition to which it will be subjected while in use, and therefore the driving surfaces are, under such corresponding operating conditions, machined to give the exact cylindrical configuration that is required for optimum results during subsequent use.

Roller bearing housing 3 is secured in a suitable work holder 15 of a machining tool generally indicated at 18. Spindle 1 is secured to a drive shaft 20 of a high-speed motor-transmission assembly (not shown). When the roller 7 has been brought up to required rotational speed, a suitable tool holder such as indicated at 22 is moved toward said roller by tool holder feed screw 24 until cutting or grinding tools 26, 28 bear against driving surfaces 9 and l 1, respectively.

Said tools 26, 28 should, of course, preferably have their cutting or grinding surfaces aligned parallel to the axis of roller 7 and equidistant therefrom.

Accordingly, the present invention enables friction rollers having driving surfaces made of a wear-resistant resilient synthetic resin material to be produced and to be used for the very high rotational operating speeds of 30,000 to 40,000 r.p.m. or even more. The problems aforementioned arising from vibrations in the spinning or twisting tubes are thus overprovement comprising the steps of: rotating said roller at a come, and this enables false-twisting spinning machines to be speed f at least 30,000 r. .m. and machining the driving suro erated at much higher rota ional peeds han h n faces of said roller to a finished state during said rotating step. heretofore possible- 2. A method according to claim 1 wherein the roller is l clam: 5 rotated during the finishing step at a speed over 30,000 r.p.m.

1. In a method for producing a friction roller suitable for driving a spinning or twisting tube at very high rotational f s s gg to g? llwherem the dnvmg Sm speeds, the roller having tube-engaging driving surfaces which aces are mac e y a men are formed of a wear-resistant resilient synthetic resin, the im- It 

1. In a method for producing a friction roller suitable for driving a spinning or twisting tube at very high rotational speeds, the roller having tube-engaging driving surfaces which are formed of a wear-resistant resilient synthetic resin, the improvement comprising the steps of: rotating said roller at a speed of at least 30,000 r.p.m. and machining the driving surfaces of said roller to a finished state during said rotating step.
 2. A method according to claim 1 wherein the roller is rotated during the finishing step at a speed over 30,000 r.p.m.
 3. A method according to claim 1 wherein the driving surfaces are machined by a diamond tool. 